Method of and apparatus for spraying liquids



Nov. 22, 1927.

N. HUBBARD METHOD OF AND APPARATUS FOR SPRAYING LIQUIDS Filed April 5 1920 INVENTOR. M W

BY .uekd

ATTORNEYS.

Patented Nov. 22, 1927.

UNITED STATES PATENT OFFICE.

NORMAN HUBBARD, OF ELIZABETH, NEW JERSEY ASSIGNOR TO THE BABCOGK G: WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD OF AND APPARATUS FOR SPRAYING LIQUIDS.

' Application filed April 5, 1920. Serial No. 371,524.

This invention relates particularly to improvements in spraying devices and spraymg methods used in ,atomizing fluids, and

' more particularly for such devices when used for spraying and atomizing fluid 011, whereby a spray is produced in which each particle is subjected to substantially the same forces by means of the mechanical action induced by pressure.

As such spra ing devices have heretofore been made, a so id column of fluid is formed and then passed through the exit of an 01'].- fice in a solid stream in Which the fluid has been given a whirling motion around the 1 axis of the column, as well as a component parallel with the axis of the column. In such a solid column it will be obvious that the particles near the center of the column will necessarily have a much slower speed of rotation than the articles more remote from the center, an consequently, when sucha column is permitted to expand at the exit of the orifice the outermost particles fly off at a very flat angle due to their 2 relatively high centrifugal force, while the particles near the center of the column, aving little or no centrifugal force, move straight forward. These particles in the center of the column are, therefore, not thoroughly atomized and tend to form into relatively large drops.

One of the objects of my invention is to provide a method and an apparatus for spraying fluids by which substantially allof the particles of the fluid passing out of the exit orifice will be subjected to substantially the same force, so that each particle will follow much the same path and so that all parts of the fluid will be equally well atomized. 1

Another object of my invention is to 1'0- vide an apparatus by which the whir ing motion given to the column will be certain and definite and not neutralized in any way by eddies which would prevent the uniform action of the device.

With these and other objects in view, my invention consists of certain novel features of construction, combination and arrangement of parts as will be more fully described and claims. r

In the accompanying drawing I have illustrated my invention as it would be applied pointed out in the appendedto a fuel burner which I have chosen for purposes of illustration.

In the drawing, Figure 1 is an enlarged sectional elevation taken on line 11 of Fig. 2 of one form of burner which I have chosen for purposes of illustration; Fig. 2 is a plan view of Fig. 1, partly in section, taken on line'22 of Fig. 1;- Fig. 3 is a top elevation of the nozzle member; Figs. 4, 5 and 6 are, respectively, plan, side elevation and bottom view of the tip illustrated in Fig. 1, Fig. 5 being partly in section, and Fig. 7 is a diagrammatic view illustrating the action in one portion of Fig. 1.

Similar reference numerals indicate similar parts in the several views.

Referring to the form of my invention shown in Figs. 1 to 7, inclusive, 20 is a nozzle member threaded to a supply pipe 21 and provided with a cavity*22. In the end of the nozzle 20 is formed an annular cavity 23 connected with the cavity 22 by ducts 24.

On the end'of the nozzle 20 is a tip 25 provided with a conical depression in its ase adapted to fit over a conical projection 26 formed on the end of the nozzle 20, which projection forms the interior wall of the annular recess 23. Over the top of the tip 25. is placed a cap 27 which fits the exterior of the tip and is screw-threaded to the nozzle 20 to hold the tip in position.

, The tip is provided with a relatively large central orifice 28, the center of which is occupied by a member 29formed on the end of the projection 26 on the end of the nozzle. 20. By reason of the presence of the projection 29,.the orifice 28 becomes an annular one.

Connecting the annular cavity 23 with the orifice 28 are a plurality of ducts 30 formed in the tip 25 and located so as 'to be tangential to the orifice 28,. and also preferably so as tohave a direction toward the exit and at an angle to the axis thereof.

In operation, the fluid under pressure passes from the chamber 22 through the ducts .24 to the cavity 23. From this int it passes through the ducts 30 into the orifice 28 and thence out of the orifice. The direction-given to the fluid as it passes into the orifice 28 is indicated in Figure 7, it bein understood that while the particles of flui are bein whirled around the orifice, they are also ing driven toward the exit end by reason of the angular relation of the ducts 30. Consequently, the fluid moves in a uniform path through the relatively small 311' nular orifice 28'without loss of velocity and the fluid therefore emerges in a cone of uniformly divided spray.

It will be noted that by the arrangement just described, the centrifugal force to which the fluid is subjected as it passes from the exit of the orifice, is very large for the quantity of fluid discharged. F or instance, if the chamber 28 were a solid cylinder, that is, did not have the projection 29 therein, its outside diameter would necessarily be very much smaller for the same rate of discharge of fluid, and consequently, even the outermost portion of the column would not be moving on as large a radius as the innermost portion of the annular column projected bymy device for the same rate of flow. Consequently, the velocity of rotation and, therefore, the centrifugal force ,tending to atomize the fluid, is much greater in this construction than would be possible for a solid column, the rates of discharge being the same in the two cases. Moreover, because the area of the exit of the orifice is the same as the entrance area at the inner part of the chamber 28, there is no loss in velocity of the particles as they move from the entrance to the exit. The walls of the annular chamber 28 being smooth and continuous, and there being no sudden changes in diameters in the chamber, the fluid moves smoothly therethrough without the production of eddies which wouldin any way interfere with the direction or velocity of the particles constituting the column of fluid movin through this chamber or orifice.

In t e form illustrated, it is essential, because of the very small space between the outer diameter of the exitof the orifice and @the central projection, that the tip shall be held in a definite, fixed relation with the projection; otherwise, a slight shifting would cause the column to be formed with thicker walls on one side than on the opposite side, thus producing an un-uniform distribution of the fluid in the spray. This centering is provided for in the form illustrated by a cooperation of the centering members described.

While I have herein shown and described one embodiment of my invention, I do not desire to be limited to the exact arrangement shown and described, but seek to cover, in the appended claims, all those modifications which come within the true spirit and scope of my invention.

I claim 1. In a device for spraying fluid fuel, a nozzle and a tip removably secured thereto, said tip be' provided with a substantially cylindrical discharge opening and said noz zle being provided with a stem extending into said opening in spaced relation to the walls thereof to form therewith an unobstructed annular discharge orifice, and means for introducing the fluid fuel to said orifice under pressure and in a whirling movement.

2. In a device for spraying fluid fuel, a nozzle and a tip removably secured thereto, said tip being provided with a substantially cylindrical discharge opening and said nozzle being provided with a stem extending into said opening in spaced relation to the walls thereof to form therewith an unobstructed annular discharge orifice, and ducts arranged to introduce the fluid fuel into said orifice tangentially whereby a whirling movement is imparted to the column of fluid fuel therein.

3. In a device for spraying fluid fuel, a nozzle and a tip removably secured thereto, said tip being provided with a substantially cylindrical discharge opening and said nozzle being provided with a stem ex tending into said opening in spaced relation to the walls thereof to form therewith an unobstructed annular" discharge orifice, and ducts inclined inwardly and towards said orifice and arranged to introduce the fluid fuel into said orifice tangentially whereby a whirling movement is imparted thereto.

4. In a device for spraying fluid fuel, a nozzle and a tip removably secured there to, said tip being provided with a substan tialy cylindrical discharge opening and said nozzle bein provided with a stem extending into said opening in spaced relation to the walls thereof to form therewith an unobstructed annular discharge orifice, and ducts inclined inwardly and towards said orifice and arranged to introduce the fluid fuel into said orifice tangentially and without substantial change in direction of the fluid fuel as it passes from the ducts to the discharge orifice.

5. A spraying. device having an annular discharge orifice comprising a chamber, the exit area of which is at least as small as the entrance area thereof, and ducts adapted to deliver liquid tangentially to the outer walls of said chamber and at an angle to the axis thereof, said outer walls forming a smooth,

continuous path from the entrance to the exit of said chamber.

6. The method of spraying fluid which consists in forming in an annular chamber open at one end and having a section of large diameter in relation to the area of the annulus, an annular column of the fluid with- 7. The method of spraying fluid fuel which consists in forming in an annular chamber open at one end and having at section of large diameter in relation to the areaof the annulus, an annular column of the fluid with the particles therein rotating around the axis of the column and also moving lengthwise thereof with no sudden changes in diameter or area, of the column throughout its length, and permitting the 10 particles to fly outward unconfined when the end of the annular chamber is reached.

NORMAN HUBBARD. 

